(1) Field of the Invention
The present invention is directed to a rocket engine, such as a booster rocket engine, using gaseous hydrocarbon in a catalytically enhanced gas generator cycle.
(2) Prior Art
A major issue with a LOX/kerosene propellant combination in high thrust rocket engine applications is instability. Pressure fluctuations in the combustion chamber have large enough values to cause harm to the structure are what is referred to as instability. Gas dynamic driven pressure variations that are driven by atomization and chemical instabilities at particular frequencies are the source of instability issues. These vibrations are usually high frequency (1000 Hz or higher) and can be very damaging.
During the combustion process, liquid fuel (kerosene) must be vaporized and cracked into its subcomponents in order to combust and this vaporization time that the kerosene droplet needs is one of the key factors in the kerosene instability issue. As the droplets enter the combustion zone, the radiant energy causes the droplets to vaporize faster and the combustion front moves closer to the faceplate. However, the faceplate is cool so that the droplet size increases and the flame front moves back down. Since the combustion causes a sharp pressure increase, a pressure wave forms. These form axial waves to set up in the chamber. The larger the chamber diameter, the more the chances of an instability occurring.